This invention relates to a novel method of working the outer periphery of circular or polygonal articles with a laser beam.
Techniques have heretofore been developed for welding, cutting or drilling workpieces with laser light as disclosed in U.S. Pat. Nos. 2,989,614 and 3,301,949. However, these techniques in which a laser beam is applied to the surface of the workpiece perpendicularly thereof are unable to form a desired smooth surface or indentations of specified depth in the outer periphery of the workpiece over a wide area or to form an annular groove of desired shape in the periphery of the workpiece. It is also well known to mechanically machine or grind the outer periphery of a rotating workpiece, but this method not infrequently involves difficulties, is inefficient or requires an apparatus of large capacity. For example, when machining the outer periphery of a rolling roll to a smooth surface for correction, the conventional mechanical machining method requires a large-scale apparatus and therefore involves the necessity of removing the roll from the rolling mill before machining. Further in machining the outer periphery of a bolt head, nut or like workpiece having a polygonal outer periphery, the workpiece is cut first at the corner portions with use of a tool while the workpiece is being driven at a specified speed, thus subjecting the tool to great resistance and impact which cause damage to and wear on the tool and presenting difficulty in machining or resulting in a reduced operation efficiency. In fact, a method remains yet to be provided by which the outer periphery of workpieces can be machined free of these problems, with improved efficiency and by the use of simple equipment.